Method of shredding worn out tire casings and a device for applying the method

ABSTRACT

The method for shredding wornout tire cases comprises exposing wornout tire cases to the effect of an explosion exerted thereon in a closed circular system so as to establish a directional circulating flow of explosion products. The device for carrying the method into effect comprises a chamber (1, 2) and a piping (3, 4) which forms, together with the chamber, a circular closed system, the chamber has a portion shaped as a cone-frustum shell (1), wherein shredding members (7) and a fixing unit of the explosive (13) are accommodated; a the smaller-diameter portion of the cone-shaped shell (1) communicates with one end of the piping (4) through a valve appearing as, e.g., a grid established by plates (7) in the area of the smaller base of the shell (1), while the other end of the piping (3) communicates with the chamber (1, 2) from the side of the larger-diameter portion of the cone-shaped shell (1).

TECHNICAL FIELD

The present invention relates in general to salvaging industrial anddomestic wastes and more specifically to technology of processingwornout tire cases of automobiles or of other machinery, predominantlythose with metal cord, as well as to devices for practical applicationof said technology.

BACKGROUND ART

At present salvaging wornout cases of auto- and tractor air-core tireswith metal cord is a serious technical and ecological problem, becausethe existing technologies of their processing are uneconomic due to muchmaterial and power consumption.

One prior-art method for shredding wornout tire cases is known to usetheir mechanical shredding with the aid of a shredder unit having twoshafts rotating against each other and carrying disks and toothedsleeves (SU, A1, 633,601).

However, said method suffers from high power consumption, involves useof sophisticated bulky equipment, and necessitates periodical outages ofthe technological process for replacing quickly wearing-out knifeblades, especially when used for processing metal-cord cases.

One more method for shredding wornout metal-cord-reinforced tire casesis known to comprise cooling the cases down to the state ofembrittlement, followed by their mechanical breaking and crushing, usinga device having two disintegrators appearing as a die and a punch.

However, said method and disintegrator unit require also much power tobe consumed, which is due to a necessity for producing and using aconsiderable amount of liquid nitrogen.

Known in the art presently is a method for destroying articles made fromcomposites and rubber-like materials, in particular, wornout tire cases,said method comprising preconditioning the cases and their shredding byvirtue of an explosion (SU, A1, 1,614,843). However, according to themethod, the cases are shredded into large pieces and therefore needfurther disintegration, using other techniques. Moreover, the methodsuffers from low disintegration efficiency and low utilizationefficiency of explosion energy.

A device for explosion destruction of wornout tire cases comprises atrough-shaped chamber, and a receptacle for shredded rubber, as well asa unit for fixing the explosive in place (SU, A1, 1,614,843).

However, said device fails to provide an efficient shredding ofmetal-cord-reinforced tire cases nor does it meet the requirements ofsafety engineering adopted in blasting operations.

DISCLOSURE OF THE INVENTION

The present invention has for its primary object to provide higherefficiency of shredding metal-cord-reinforced tire cases and lower powerand material consumption.

The foregoing object is accomplished due to the fact in a method,comprising preconditioning tire cases and their shredding by means ofexplosion, according to the invention, an explosive action is exertedupon the tire cases in a closed circular system so as to establish adirectional circulating annular flow of explosion energy and fragmentsof shredded tire cases.

According to a specific embodiment of the method, the fragments of tirecases are subjected to a repeated explosive action in a recirculatedannular flow formed by the explosion product. According to otherspecific embodiments of the proposed method, the desired results isattained due to the fact that preconditioning metal-cord-reinforced tirecases for explosion-shredding involves their treating withhigh-frequency currents, or inductor-heating of the cord wire, or elsecooling the tire cases.

The foregoing object is accomplished also due to the fact that a devicefor destructing and shredding wornout tire cases, comprising a chamberfor their accommodating and an explosive fixing unit, according to theinvention, is provided with shredding members and a piping which form,together with the chamber, a circular system, while the chamber has aportion shaped as a cone-frustum shell, wherein the shredding membersand the explosive fixing units are accommodated; a smaller-diameterportion of the cone-shaped shell communicates with one piping endthrough a valve, while the other piping end is connected to the chamberfrom the side of larger-diameter portion of the cone-shaped shell.

According to other specific embodiments of the device, the shreddingmembers on the cone-shaped shell appear as plates located in an axialplane thereof, said plates having cutouts that establish a space foraccommodating the tire cases to be shredded; the valve appears as a gridlocated in the area of a smaller base of the cone-shaped shell; thepiping is provided with grids for shredding the fragments of the tirecases; the chamber wall connecting the larger base of the cone-shapedshell to the piping appears as a cone-frustum shell, or as such a shellconnected to a transition cylindrical wall; the piping elbow located onthe side of the larger base of the cone-shaped shell is removable, whilethe stationary-fixed piping elbow has a product discharge hole. Thechamber and the piping are isolated from the surrounding atmosphere by aprotective housing, while the space between the housing and the chamber,as well as that between the housing and the piping are evacuated forsound-proofing of the device.

The essence of the proposed method and the device for carrying themethod into effect consists in that the proposed combination ofessential features makes it possible to realize the conditions underwhich in the first phase of explosion the tire cases are destructed intorelatively large fragments, while in the second phase of explosion thelarge fragments are shredded, as a result of forming a directional flowof explosion energy many-times recirculating along the annular space,upon their colliding with the shredding members housed in the chamberand piping.

BRIEF DESCRIPTION OF THE DRAWINGS

In what follows the present invention will now be disclosed in adetailed description of an illustrative embodiment thereof withreference to the accompanying drawings, wherein:

FIG. 1 is a general schematic view of the device for carrying theproposed method into effect; and

FIG. 2 is a cross-sectional view of the chamber of said device.

BEST METHODS OF CARRYING OUT THE INVENTION

The device comprises an armored chamber, consisting of a cone-frustumshell 1 and a wall 2 and establishing, together with a piping 3, 4, acircular system. The piping comprises a detachable elbow 3 and an elbow4 permanently joined to the chamber.

The piping accommodates grids 5, while the piping elbow 3 is connectedto the piping elbow 4 via a joint 6. Welded to the shell 1 are plates 7having cutouts in their upper portion which establish a space for tirecases 8 to accommodate. The chamber wall 2 is connected to the pipingelbow 3 via a joint 10.

The piping elbow 4 has a hole 11 to discharge shredded fragments of tirecases, and a valve 12 for blowing the explosion chamber. An oblongexplosive charge 13 is put in a pack of tire cases to be shredded. Thechamber 1, 2 and the piping 3, 4 are enclosed in a housing, while thespace between the housing and the device is evacuated for bettersoundproofing and heat insulation of the device. The amount of saidspace (gap) exceeds the linear displacements of the chamber and pipingunder the effect of an explosion.

The proposed method comprises also the operations of preconditioning thetire cases before shredding, which may include their washing, separatingthe bead-forming rings, compacting the tire cases, treating the metalcord with high-frequency currents or its heating in an inductor fordecreasing the cord-to-rubber adhesion or cooling the tire cases so asto embrittle the rubber, and some other operations aimed at facilitatingcord separation from rubber.

A pack of the preconditioned tire cases 8 is inserted in the chamberthrough an opening in the wall 2 resulting from removal of the pipingelbow 3, and is placed in the space formed by the cutouts in the plates7. Then the explosive charge 13 is put in the pack of tire cases, and aclosed circular system is established by establishing communicationbetween the piping elbow 4 and the opening in the wall 2, using thepiping elbow 3 and the joints 6 and 10.

The device of the present invention operates as follows.

The explosive charge 13 is fired, with the result that in the firstphase of explosion the tire cases 8 are displaced radially and getdestroyed into large fragments under the action of the plates 7. In thesecond phase of explosion a directional flow of explosion energy andfragments of the destructed tire cases is established to circulate inthe aforementioned closed circular space, this being due to theconstruction arrangement of the chamber. It is under the action of thegrids 5, the plates 7, strips 9, and the walls of the chamber (1, 2) andof the piping (3, 4) that the fragments of tire cases undergo additionalshredding and the explosion energy of the circulating flow is absorbed.

Once the explosion products have stopped circulating, the valve 12 isopened for the explosion chamber to blow down, whereupon the shreddedfragments of the tire cases are discharged through the hole 11 andseparated into rubber crumb and metal cord and fragments of bead-formingrings (if they have not been separated at the stage of preconditioningof the tire cases).

The resultant products of shredding of tire cases may be subjected tofurther disintegration either mechanically or by a repeated use ofexplosion energy according to the proposed method. In the latter casethe fragments of tire cases are loaded in the armored chamber and aresubjected to further disintegration in a circulating explosion flow.Reshredding of the fragments may be effected also without reloading theproduct.

Given below are some specific exemplary embodiments of the proposedmethod.

EXAMPLE 1

Size 6.45×13 metal-cord-reinforced tire cases are subjected toshredding. Once having been washed the tire cases are arranged in a pack(five items each) and are placed in the armored chamber. Then acylinder-shaped explosive charge is inserted in the pack, said chargeconsisting of powdered ammonium nitrate (70%) and trinitrotoluene (30%)and having a total weight of 1 kg.

The charge is fired from type -8 electric fuze. A maximum size offragments resulting from explosion-shredding of tire cases by the methoddisclosed herein is not in excess of 50 mm, and the amount of fractionssizing less than 20 mm is about 25% of a total weight of rubber andmetal cord. A maximum size of fragments of the destructed bead-formingrings is 50 mm.

EXAMPLE 2

The fragments of tire cases resulting from Example 1 and having the sizeof from 20 to 50 mm is subjected to further shredding. The explosionprocedure is carried out in a way similar to Example 1. A maximum sizeof the fragments of tire cases resulting from the second shreddingprocedure is not in excess of 20 mm. Then the resultant product ismechanically disintegrated and rubber crumb is separated from metalcord.

EXAMPLE 3

Size 6.45×13 metal-cord-reinforced tire cases are preconditioned forfurther shredding by being treated with high-frequency currents forreducing adhesion of cord wire to rubber. The product having thefollowing composition is obtained as a result of explosion shredding asdescribed in Example 1: maximum size of tire case fragments, 50 mm;amount of fractions sizing less than 20 mm, 35 wt. %; proportion ofmetal cord completely separated from rubber, about 70%.

EXAMPLE 4

Metal-cord-reinforced tire cases are preconditioned for furthershredding by being cooled with liquid nitrogen and then areexplosion-shredded as in Example 1. The resultant fragments have amaximum size of 10 mm and the amount of rubber crumb sizing less than 3mm is 50 wt. %.

EXAMPLE 5

After having been preconditioned the tire cases as in Example 1, theyare heat-treated in an inductor so as to reduce metal-cord-to-rubberadhesion. Then the tire cases are explosion-shredded as in Example 1 toobtain the product featuring a maximum size of tire case fragments notexceeding 50 mm and the amount of fractions sizing less than 20 mm, 30to 35%, while the proportion of metal cord separated from rubber isabout 70%.

Industrial Applicability

The method and the device for carrying said method into effect areinstrumental in attaining higher efficiency of an effect of explosion soas not only to destruct a tire case but also to shred the resultantfragments thereof. Practical use of the method involves the use of butsimple equipment, and the preparation procedure for explosion operationsconsists of simple operations. Application of the technological processaccording to the proposed method curtails substantially the amount ofconsumed power and the costs of destruction and shredding of tire cases.

Experimental check of the method and testing the device for itsrealization give evidence that the technological process for shreddingtire cases may be realized with a strict adherence to the most stringentrequirements imposed on safety engineering adopted in blastingoperations and on ecological safety.

The proposed method and device for shredding wornout tire cases can findwidespread industrial application at salvage processing enterprises,including those located at places for storage of wornout tire cases.

What is claimed is:
 1. A method for shredding used tire casescomprising:placing said tire casings in an explosion-proof chamberhaving a closed circular flow system; and detonating an explosive chargeamong said tire casings to generate a circulating annular flow ofexplosion products within said chamber.
 2. A method according to claim 1further comprising preconditioning said tire cases to reduce theirstrength.
 3. A method as set forth in claim 2, CHARACTERIZED in thatpreconditioning tire cases involves their treating with high-frequencycurrents.
 4. A method as set forth in claim 2, CHARACTERIZED in thatpreconditioning tire cases involves induction heating of metal cord withcommercial-frequency currents.
 5. A method according to claim 2CHARACTERIZED in that preconditioning tire cases involves cooling.
 6. Amethod as set forth in claim 1, CHARACTERIZED in that the fragments oftire cases are further shredded by a repeated explosive action.
 7. Adevice for shredding wornout tire cases (8), comprising a chamber (1, 2)for their accommodating and a fixing unit of an explosive (13),CHARACTERIZED in that within the chamber are provided shredding members(7) and a piping (3, 4) which form, together with the chamber (1, 2), acircular system, while the chamber (1, 2) has a portion shaped as acone-frustum shell (1), wherein the shredding members (7) and the fixingunit of the explosive (13) are accommodated; the smaller-diameterportion of the cone-shaped shell (1) communicates with one end of thepiping (4) through a valve, while the other end of the piping (3)communicates with the chamber (1, 2) from the side of thelarger-diameter portion of the cone-shaped shell (1).
 8. A device as setforth in claim 7, CHARACTERIZED in that the shredding members (7) on thecone-shaped shell (1) appear as plates (7) located in an axial plane ofthe chamber (1, 2), said plates having cutouts that establish a spacefor accommodating the tire cases (8) to be shredded.
 9. A device as setforth in claim 8, CHARACTERIZED in that the valve appears as a gridlocated in the area of a smaller base of the cone-shaped shell, and thegrid is formed by the plates (7) secured on the shell (1).
 10. A deviceas set forth in claim 6, CHARACTERIZED in that grids (5) are located inthe piping (3,4).
 11. A device as set forth in claim 6, CHARACTERIZED inthat the wall of the chamber (2) connecting the larger base of thecone-shaped shell (1) to the piping (3, 4) appears as a cone-frustumshell (2), or as such a shell connected to a cylindrical pipe connector.12. A device as set forth in claim 6, CHARACTERIZED in that the pipingelbow (3) located on the side of the larger base of the cone-shapedshell (1) is removable, while the stationary-fixed elbow (4) of thepiping (3, 4) has a product discharge hole (11).
 13. A device as setforth in claim 6, CHARACTERIZED in that the chamber (1, 2) and thepiping (3, 4) are enclosed in a housing (14), and the space (gap)between the housing (14) and the chamber (1, 2), as well as that betweenthe housing (14) and the piping (3, 4) are evacuated, while the amountof said space (gap) exceeds the linear displacements of the chamber (1,2) and of the piping (3, 4) under the effect of an explosion.